North American coral recovery after the end-Triassic mass extinction, New York Canyon, Nevada, USA
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A Triassic-Jurassic (T/J) mass extinction boundary is well represented stratigraphically in west-central Nevada, USA, near New York Canyon, where the Gabbs and Sunrise Formations contain a continuous depositional section from the Luning Embayment. The well-exposed marine sediments at the T/J section have been extensively studied and reveal a sedimentological and paleontological record of intense environmental change and biotic turnover, which has been compared globally. Unlike the former Tethys region, Early Jurassic scleractinian corals surviving the end-Triassic mass extinction are not well-represented in the Americas. Here we illustrate corals of Early Sinemurian age from Nevada located at three horizons above the T/J boundary. These well-preserved corals represent one of the earliest Jurassic appearances in North America and the earliest in the United States. Their co-occurrence with bivalves, gastropods, and ammonites adds additional faunal elements to the study. The corals are exclusively solitary and occur in profusion packed within beds. They all belong to the family Stylophyllidae, known to have been extinction resistant. These post-extinction corals support the Hispanic Corridor hypothesis and provide new data on biotic recovery following the end-Triassic mass extinction.
Manuscript received 6 Mar. 2015; accepted 9 July 2015.